Ni-Mn based ternary Heusler compounds have drawn attention lately as significant magnetocaloric effects in some of them have been observed. Substitution of Ni and Mn by other $3d$-transition metals in controlled quantity has turned out to be successful in enhancing the effect and bring the operational temperatures closer to room temperature. Using density functional theory calculations, in this work, we have systematically explored the roles of various factors such as site occupancies, magnetic interactions, and compositions associated with the constituents of Mn-excess ${\mathrm{Ni}}_2\mathrm{MnSb}$ Heusler compounds upon substitution of Ni and/or Mn by $3d$-transition metals Fe, Co, and Cu. Our calculations unveiled the physics behind the variations of physical properties associated with the magnetocaloric effects, and thus interpreted the available experimental results successfully. The work also provided important information on the compounds and the composition ranges where significant magnetocaloric effects may be realized, and further experimental investigations need to be done.

中文翻译：

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了解替代Ni-Mn-Sb-Z（Z = Fe，Co，Cu）化合物中磁热效应的起源：第一性原理计算的见解

Ni-Mn基三元Heusler化合物近来引起了人们的注意，因为其中一些化合物具有显着的磁热效应。镍和锰被其他取代$3d$事实证明，控制量的过渡金属可以成功地提高效果，并使工作温度接近室温。使用密度泛函理论计算，在这项工作中，我们系统地探索了各种因素的作用，例如位点占用，磁相互作用以及与锰过量元素相关的成分${你}_2\mathrm{锰锑}$ 用Ni和/或Mn取代的Heusler化合物 $3d$-过渡金属Fe，Co和Cu。我们的计算揭示了与磁热效应相关的物理性质变化背后的物理原理，从而成功地解释了可用的实验结果。这项工作还提供了有关可能实现显着磁热效应的化合物和组成范围的重要信息，需要进行进一步的实验研究。